Analysis of reverse transcription showed that leaf extract induced two genes involved in protection from oxidative stress, katA and katB which encode catalases A and B respectively and are associated HSP inhibitor with the detoxification of reactive oxygen species produced as a consequence of aerobic metabolism, or the presence of

iron and/or toxic molecules in the plant extracts (Figure 5) [52, 53]. Most bacterial catalases require haem groups for catalytic activity; the final step of haem synthesis is catalyzed by ferrochelatase, which condenses Fe2+ into protoporphyrin IX. In P. aeruginosa, the cellular source of iron required for haem assembly is the protein bacterioferritin A, encoded by the bfrA gene, that is required as an iron supplier for the haem group of KatA and thus for protection against H2O2 [54]. Our results show that gene bfr2 encoding an iron storage bacterioferritin was induced under the effect of bean leaf extract and apoplastic fluid, which may supply iron for catalase activity (Figure 3, Table 1). In summary, the increased growth in media supplemented with plant extracts can be associated with nutrient assimilation and active metabolism. In these conditions we identified genes involved in carbon and nitrogen utilization, chaperones, heat shock proteins and those involved in protection against

oxidative stress (Table 1). Some of the identified genes such as heat shock proteins, bacterioferritin, and genes

involved in defense against oxidative stress are positively regulated by the Ferric uptake regulator protein (Fur) [55]. These findings suggest that aerobic metabolism AZD0156 mouse is active during contact with plant tissues, as will be discussed below in the section describing repressed genes (Figure 5). Additionally 16 genes were grouped into two clusters. Cluster V includes 11 poorly characterized genes; seven of these are preferentially induced by leaf extract and may have functions related to responses to signal molecules present in the extracts. Some other induced selleck genes that could not be classified as being involved in a particular biological process, were included in Cluster VI, two genes involved in chemotaxis, two transcriptional regulators of the AraC and GntR families and four genes which may be related to membrane biogenesis (Figure 3 and Table 1). Bean leaf extract and apoplastic fluid down-regulate genes involved in iron uptake and metabolism Cluster VII was the largest cluster and contained 24 genes repressed in response to bean leaf extract and apoplastic fluid (Figure 3). Thirteen of these genes are known or hypothesized to be associated with pyoverdine production. This group includes pvdS, an extracytoplasmic sigma factor (ECF) needed for the transcription of genes for pyoverdine synthesis, a ferripyoverdine receptor (FpvA) involved in binding of iron-siderophore MM-102 research buy complexes in P.